1. Technological Field
The present disclosure relates generally to the field of content and/or data delivery over a network. More particularly, the present disclosure is related, in one exemplary aspect, to apparatus and methods for management of quality of experience for content delivery.
2. Description of Related Technology
Digital video has traditionally been delivered to clients without buffering in a real-time fashion with a central controller managing the network configuration of different services, whether delivery is broadcast, on-demand, or switched service. With the proliferation of Internet Protocol (IP) content and buffered clients, the client is principally responsible for determining the optimal Quality of Experience (QoE) at individual endpoints. Within these buffered client architectures, clients are given a manifest file or index containing the various bitrates and encodings of requested video content, often referred to as video profiles. Upon initiating delivery of a stream of content, the endpoint device (e.g., client device) algorithmically selects a particular video profile, for example the profile with the highest bit rate/quality, based on network capacity (or prediction thereof) from the perspective of the endpoint device.
Present IPTV solutions are based on “best-effort” delivery principles, and do not guarantee a Quality of Service (QoS). In such best-effort service, minimum performance metrics such as bit rate, latency, jitter, or loss are not guaranteed. IPTV video streaming over best-effort services incorporates feedback mechanisms into the IP endpoints (e.g., client devices) that allow the video streams to be adapted to the current network conditions as observed from the endpoint in real-time, such as via the use of Adaptive Bitrate (ABR) systems. However, from the perspective of an endpoint user, IPTV content may suffer from protracted and distracting effects of conditions such as (i) slow start-up negotiation of a format for delivering the requested video content, (ii) mid-program resolution changes of the video content, and occasionally (iii) a total failure of the video stream delivery.
In Hypertext Transport Protocol (HTTP) based video delivery paradigms, video may not be continually streamed to the client device per se, rather the client may perform a series of requests for blocks or portions of the video content. In one common implementation, the client device monitors an internal playout buffer before requesting the next block of video data. The client device may for example continually monitor and predict its own buffer under-run condition (i.e., the buffer draining faster than it is being replaced by the incoming content). Upon experiencing an under-run condition, the client may request to downshift from the current bitrate content to a lower bitrate selection, guided by what the client either measures or predicts about network capacity of the link. The downshift is an attempt on the part of the client device to avoid starvation of its buffers that can cause visual and audio faults or discontinuities in the playback of content, thereby negatively impacting the QoE (quality of experience) for a user.
At a high level, transitioning a network to IP content delivery has a number of benefits for Managed System Operators (MSO). Such benefits include (i) the ability to offer branded content and enhanced video services, (ii) reduced equipment costs in both the head-end and customer premises, (iii) emergence of the software client as a means of playing video content on a wide range of consumer equipment devices, (iv) ease of integration with open standards (e.g., HTML 5), and (v) the ability to match or exceed the quality of experience provided by traditional digital video transport over e.g., Quadrature Amplitude Modulation (QAM). Furthermore, IP is agnostic to the access medium used to deliver the content.
However, the Federal Communications Commission (FCC) has challenged Internet Service Providers (ISP) and operators to conform to a mandate, commonly known “Network Neutrality”. Network Neutrality is intended to limit what ISPs are allowed to control with regards to the traffic transported over their network. In particular, network policies which impact the content of a competitor relative to the ISP or operator's own content are expressly forbidden. Accordingly, a MSO may violate Network Neutrality rules by implementing Quality of Service (QoS) for the MSO's own IP content in an effort to improve the IP content delivery (as compared to best-effort service techniques).
Hence, flexible management tools and methods for managing a user's quality of experience of IP content delivery over a network (including addressing potential issues raised by Network Neutrality) represents one salient need presented by the foregoing situation. Ideally, such tools and methods should allow for implementation of services for managing quality of experience within a wide variety of network architectures and delivery paradigms.